PIG SYNOVIUM .2. SOME PROPERTIES OF ISOLATED INTIMAL CELLS

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  • 1 January 1977
    • journal article
    • research article
    • Vol. 123  (FEB) , 47-66
Abstract
Certain physiological and immunological properties of the individual synoviocytes were examined isolated and cultivated in various in vitro systems. Suspensions of intimal synoviocytes were obtained by incubating sheets of joint capsule from the metacarpophalangeal joint in a solution of trypsin and then scraping off the intimal cells with a small knife. In a freshly prepared suspension many intimal cells were still branched, but after 1 1/4 h incubation in a small tube in serum-containing medium, the majority of cells had withdrawn their processes and become rounded. The branched cells had little capacity for phagocytosis, but those in the rounded form were actively phagocytic. When incubated with opsonized sheep erythrocytes, most of the rounded but none of the few remaining branched cells had acquired rosettes of red cells. Since the trypsin treatment probably altered the cell surface, the experiments were repeated on intimal cells maintained in Sykes-Moore chambers for 24-48 h. Although the original synovium contains only a small proportion of macrophage-like A-cells in the cultures the population consisted mainly of cells indistinguishable from normal macrophages with a few colonies of fibroblasts. Unlike the fibroblasts, the macrophage-like cells were highly phagocytic and formed conspicuous rosettes when exposed to opsonized red cells. When cultivated in the presence of antiserum to pig erythrocytes, the macrophage-like cells fused to form large lakes of multinucleated cytoplasm. Intimal synoviocytes apparently belong to a single cell type and assume the A- or B- form according to local environmental conditions.